"$.entwine is not a function" error with TreeMultiSelectField in a Front End Form

I need to select multiple parent / child categories in a front end form, I am using a TreeMultiSelectField to achieve this in SilverStripe 3.5.1 and can successfully populate this dropdown in the CMS Page, but when I add to my front end form the field doesn't render and I get the following errors in the browser console:

I'm not entirely sure this would resolve your issue, because I ran into this error message in a different context (using zenvalidator, newest version, which ships with parsley 2.5 and interacts with SS's version of entwine but my site uses jquery 2+). It turns out that in my case the jquery version was so new, it no longer had browser detection built in. So I solved it by adding the jquery browser plugin as suggested through this post: https://stackoverflow.com/questions/14793331/uncaught-typeerror-cannot-read-property-msie-of-undefined